1. Field of the Invention
The present invention relates to a portable terminal system for taking an image in which a digital watermark is embedded and extracting the digital watermark from the image and to an operation method thereof.
2. Description of the Related Art
Hitherto, a digital watermark technique has been known. In this technique, additional information (digital watermark), such as information about a copyright holder, is embedded in a still image, a moving image, sound, and so on such that the digital watermark cannot be recognized visually or aurally.
As an embedding method, the following are known. An image or sound is transformed to frequency components, a digital watermark is embedded in a specific component, such as a high frequency component, and then the frequency components are inversely transformed. Alternatively, a digital watermark may be embedded in an image or sound by adding/subtracting a predetermined value to/from the image or sound in a predetermined period.
A function of embedding a digital watermark into an image and a function of extracting a digital watermark from an image are often used for the purpose of protecting copyrights and preventing falsification. In these cases, high-definition/multiple tone images are often used. Accordingly, a stationary high-performance image processor is required.
In recent years, however, the performance of portable terminals such as portable phones has become higher, and these portable terminals can process high-definition images and high-quality sound.